Chemical examination of the root of Ipomoea orizabensis / by Frederick B. Power and Harold Rogerson.

  • Frederick Belding Power
Date:
1912
Catalogue details

Licence: In copyright

Credit: Chemical examination of the root of Ipomoea orizabensis / by Frederick B. Power and Harold Rogerson. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    0 7238, made up to 20 c.c. with chloroform, gave o,, +l°34:1 in a 2-dcm. tube, whence [a]D +21'64°. The sugar obtained by hydrolysing a small portion of the above- described acetyl derivative yielded an osazone melting at 180—182°, but this was not identical with rliamnosazone, for a mixture of the two compounds melted at 163—164°. Moreover, on acetylating a quantity of pure rhamnose no crystalline derivative could be obtained. For the purpose of comparing the properties of the sugar yielding the above-described tetra-acetyl derivative with those of rhodeose, a small quantity of the latter was kindly supplied to us by Professor E. Votocek, of Prague. This substance was in colourless, prismatic needles, melting at 144—145°, but the acetylated product could only be obtained in the form of a syrup. It may, furthermore, be noted that the phenylosazone of rhodeose has been recorded as melting at 170° (Chem. Centr., 1900,1., p. 803). is&Rhodeose yields an osazone melting at 186—187°, but the benzoylated product could not be obtained in a crystalline state (Ydouk, Btr., 1911, 44, 820). In order to ascertain whether the methylpentose con- tained in the above-mentioned syrup was capable of yielding a crystalline benzoyl derivative, portions of the syrup were treated by both the Schotten-Baumann method and by heating with benzoic anhydride, but in each case with a negative result. After the separation of the above-described tetra-acetylmethyl- pentose, the mother liquors yielded a further quantity of the same substance, and finally a more readily soluble solid was deposited. This was collected, washed with a little dilute alcohol, and then recrystallised from 70 per cent, alcohol, when it seimrated in slender needles, melting at 111—112°. After two further crystallisations the substance began to melt at 112°, but complete fusion only took place at 118°. (Found, C=49'2; H = 5'7. Calc., C = 49’2; H = 56 per cent.) This compound was thus identified as penta-acetyldextrose, CcII706(CO*CH3)5, and it apparently consisted of a mixture of the a- and /3-forms, which melt at 112° and 134° respectively. From the above results it is evident that by the acid hydrolysis of the ethyl acetate-soluble portion of the hydrolysed ethereal extract of the resin, two sugars are produced, one of which is dextrose, and in predominating amount, whilst the other is a methyl' pentose.